Nuclear summit: Goal of global security far off

WASHINGTON 
Halfway into an ambitious four-year effort to safeguard nuclear materials, President Barack Obama and other world leaders are lagging behind their self-imposed goals and facing renewed nuclear threats from Iran and North Korea.

U.S. officials expect no major announcements at next week's nuclear security summit in the South Korean capital of Seoul. Still, Obama and leaders of more than 50 nations will praise voluntary steps to corral material that could be used for terrorist weapons. The nuclear security summit is a checkup two years after Obama announced the goal in 2010.

Obama will use the gathering to keep pressure on nuclear North Korea to return to arms control talks and back off a threatened planned long-range rocket launch.